1. Field of the Invention
The present invention relates to a leaf spring load measuring device and a program for evaluating the sag resistance of a leaf spring.
2. Description of the Related Art
A generally known hard disc drive contains therein a magnetic disc, a magnetic head for writing information to and reading it from the disc, and a leaf spring called a suspension that supports the head on its distal end. The spring is bent toward the disc and presses the head against the disc. When the disc rotates, the head and the spring float under the influence of an airflow that is generated above the surface of the disc. In this floating state, the head can write information to or read it from the disc.
Nowadays, with the recording densities of magnetic discs being improved drastically, setting the load of the leaf spring that has the aforesaid function requires very high precision. Therefore, a high-precision load measuring device is used to measure the load of the leaf spring. The load measuring device comprises a damper that supports the leaf spring, a load cell that causes a probe to abut against the spring, and a lift mechanism that raises and lowers the load cell.
In the load measuring device of this type, as described in Jpn. Pat. Appln. KOKAI Publication No. 2004-355678, for example, the load cell is lowered toward the load value to measure the load of the spring. If the measurement result is different from a standard one, the load is corrected by applying, for example, a laser beam.
In recent years, PCs and their peripheral devices are expected to have high resistance against shock, and so are hard disc drives. Thus, if a magnetic head is in contact with a magnetic disc when a heavy shock acts on a hard disc drive that uses a leaf spring, the spring may possibly warp and sag. In the case of a leaf spring whose load is corrected by a laser beam, in particular, residual stress in the spring is removed by the laser beam. It is necessary, therefore, to check and see whether the leaf spring with the corrected load is equivalent in sag resistance to one with its load uncorrected. This check requires a test for evaluating the sag resistance of the corrected leaf spring. However, the conventional load measuring device cannot deal with the evaluation of the sag resistance and needs some improvement.